Hello good people of TDIClub, have been lurking here since we got the first TDI in the family but this is the first time I've not been able to get by without personalized help.
Was cruising on the highway a few weeks back and suddenly it felt like car lost 3/4 of the torque. I thought maybe something triggered the limp mode but nope, cycling engine on and off changes nothing, it idles just fine and out of 5 times when gas pedal is pressed, 1-2 times it will go as it should, the other 3-4 it will go like molasses dripping uphill.
No CEL, no codes.
I suspected the sticking VNT mechanism, took the turbo off on the weekend and replaced it because some tips were damaged, but there was no change.
Tried disconnecting the MAF and it started behaving almost normal. Thought it was a clear cut case, but nope. Replacing the MAF changed nothing. Checked the wiring too. Everything seems fine.
After that suspicion came to the vacuum system. But again, everything checks out. Actuator works fine, n75 too, there are no leaks anywhere and vacuum holds just fine when engine is off.
I found that all vacuum check valves were shot. Thought I've found a culprit, but nope again, replaced them and it's all the same.
I even logged the engine to see what the hell was going on. I'm not sure how well I understand the logic of this ECU but from the log it seems like engine can supply the requested boost/torque just fine, it's just that requested parameters vary from acceleration to acceleration.
Anyway, here's the log and maybe someone more experienced can make heads or tails of it.
Most smaller spikes are me flooring the gas and only the last spike is when it accelerated as it should. Both the boost and injected quantity seems much higher there, which makes sense.
https://datazap.me/u/usermcuserface/log-1578665961?log=0&data=0-1-2-3-4
Was cruising on the highway a few weeks back and suddenly it felt like car lost 3/4 of the torque. I thought maybe something triggered the limp mode but nope, cycling engine on and off changes nothing, it idles just fine and out of 5 times when gas pedal is pressed, 1-2 times it will go as it should, the other 3-4 it will go like molasses dripping uphill.
No CEL, no codes.
I suspected the sticking VNT mechanism, took the turbo off on the weekend and replaced it because some tips were damaged, but there was no change.
Tried disconnecting the MAF and it started behaving almost normal. Thought it was a clear cut case, but nope. Replacing the MAF changed nothing. Checked the wiring too. Everything seems fine.
After that suspicion came to the vacuum system. But again, everything checks out. Actuator works fine, n75 too, there are no leaks anywhere and vacuum holds just fine when engine is off.
I found that all vacuum check valves were shot. Thought I've found a culprit, but nope again, replaced them and it's all the same.
I even logged the engine to see what the hell was going on. I'm not sure how well I understand the logic of this ECU but from the log it seems like engine can supply the requested boost/torque just fine, it's just that requested parameters vary from acceleration to acceleration.
Anyway, here's the log and maybe someone more experienced can make heads or tails of it.
Most smaller spikes are me flooring the gas and only the last spike is when it accelerated as it should. Both the boost and injected quantity seems much higher there, which makes sense.
https://datazap.me/u/usermcuserface/log-1578665961?log=0&data=0-1-2-3-4
